Neurological Anatomy

1. Neurological Anatomy • Nervous system- divided into 2 structural parts • Central Nervous System (CNS)- brain & spinal cord • Peripheral Nervous System – cranial nerves (carry impulses to and from brain) & spinal nerve (carry messages to and from spinal cord

2. Impulses transmitted by: Neurons- Basic structures for receiving and sending signals. Dendrites – receive signals Axons – send signals Synapse is space between axon and dendrite. Basic Anatomy

3. Brain Cerebrum Largest part of the brain, composed of 2 hemispheres and 4 lobes. Frontal, parietal, temporal and occipital.

4. Cerebrum • Frontal - Conceptualization, motor ability and judgment, thought process, emotions. • Parietal – Interpretation of sensory information, ability to recognize body parts. • Temporal – memory storage, integration of auditory stimuli. • Occipital – Visual Center.

5. Cerebellum • Cerebellum- Keeps person oriented in space, balance. Doesn’t initiate movement but coordinates it • Controls skeletal muscles • Controls voluntary movements

6. Diencephalon Area between cerebral hemispheres and the brainstem it contains: • Thalamus –relay station for the nervous system, sorts out impulses and directs them to the cerebral cortex • Hypothalamus –maintains homeostasis by controlling vital functions: temperature, heart rate, BP, pituitary regulator, emotions

7. Brain Stem • Brain stem – central core of the brain, contains midbrain, pons and medulla. • Midbrain- contains many neurons and tracts • Pons – Controls rhythmicity of respiration, contains motor and sensory pathways. • Medulla – Cardiac, respiratory, vasomotor control. Swallow, gag and cough reflex. Motor and sensory fibers cross here. • Spinal Cord – continues with the brain stem.

8. Cerebral Circulation • Originates from carotid and vertebral arteries. • Blood Brain Barrier: Prevents diffusion of toxic substances and large molecules. • Cerebrospinal fluid: Contains: no RBC’s, few WBC’s, Glucose 45-75mg/dl, Protein 15-45 mg/dl.

9. Coverings of the Brain & Spinal cord • Meninges: 3 layers tissue Dura mater Arachnoid layer Pia mater Spaces: Epidural Subdural Subarahnoid

10. Functional Divisions • Functional divisions of Nervous System: • Central Nervous System: Brain and spinal cord, receives and conducts stimuli. • Autonomic Nervous System: Regulates autonomic body functions, ex. Heart rate. • Sympathetic- maintains homeostasis and defense against stressors. Fight/flight • Parasympathetic- Restorative and vegetative functions; Decrease heart rate, dilates blood vessels constricts pupils. S= Stress and P= Peace.

11. CNS PATHWAYS • Crossed representation: Left cerebral cortex controls right side of body and vice versa • Sensory pathways:afferent pathways from peripheral to central • Motor pathways:efferent pathways from central to peripheral • Cranial nerves (12 pairs) enter & exit brain • Spinal nerves (31 pairs) enter & exit spinal cord

12. Headaches Head injury Syncope (faint) Dizziness Vertigo (rotational spinning) Seizures Tremors Paresthesia (burning/numbness/tingling) Dysphagia (difficulty swallowing) Dysphasia (difficulty speaking Significant past Hx Environmental/occupational hazards Neurological Assessment Subjective

13. Mental Status Assessment • Level of Consciousness (LOC): alert, somnolent, stuporous, comatose. • Orientation: person, place, time = A&O x 3. • Memory: • Immediate, recent and remote

14. Cognitive Assessment • Thought process • Calculations • Current events • Response to proverbs • Judgment & problem solving ability • Communication abilities • Emotion- Mood and affect

15. Cranial Nerve Assessment • Cranial nerves – 12 pairs, motor, sensory, mixed function. • CN 1 – Olfactory (sensory) – smell. • CN 2 – Optic (sensory) – sight. • CN 3 – Oculomotor (motor) – eye movements • CN 4 – Trochlear (motor) – eye movements • CN 5 – Trigeminal (motor & sensory) chewing( and pain sensations of face. • CN 6 – Abducens (motor) eye movements

16. Cranial Nerve Assessment • CN 7 – Facial (motor) – facial expressions • CN 8 – Vestibulocochlear (acoustic) – hearing • CN 9 – Glossopharyngeal – swallowing • CN10 – Vagus – swallowing, gag • CN11 – Spinal Accessory – trapezius, sternomastoid muscles • CN 12 – Hypoglossal – motor – tongue.

17. Motor Function Assessment • Motor function- Test motor strength and compare bilaterally. Scale used: 5 = Full ROM full resistance 4 = Full ROM some resistance 3 = Full AROM 2 = Full PROM 1 = trace movement, flicker finger • Muscle size • Involuntary movements?

18. Muscle Tone Assessment • Muscle Tone- ranges from flaccid to taut • Atonia - no muscle tone, no resistance • Hypotonia-slight muscle tone, little resistance • Hypertonia- too much resistance • Spasticity- stiff, awkward movements • Rigidity- tightness, inability to bend • Involuntary movements- tics, fasciculations (fine tremors) and tremors (resting or intentional).

19. Sensory Assessment Sensory Function: Perform all sensory testing with the patient’s eyes closed and test bilaterally. • Spinothalamictract- pain, temp. touch • Posterior (Dorsal) Columns – position (proprioception), vibration and tactile discrimination (fine touch)

20. Sensory Assessment • Vibration – tuning fork to bony prominence • Position (kinesthesia) – Grasp toe or finger and move it up/down or side/side. • Stereognosis – place object in hand to identify (coin, paperclip). • Graphesthesia – trace letter or number on palm to identify.

21. Cerebellar Function Assessment • Posture and gait – steady gait with arm swing, balance maintained. • Romberg test – Have pt. stand, feet together, arms side, eyes closed. • Heel to toe gait – tandem walk

22. Cerebellar Function Assessment • Rapid Alternating Movements (RAM) Hand movements- Tap finger to thumb, rapidly. Tap each finger to thumb rapidly. Pronate and supinate hands rapidly on knees • Finger to nose test – Eyes closed touch finger to nose alternating and increasing speed • Finger to finger test - Have pt. touch his fingertip to your fingertip, alter position. • Heel to shin test – While supine or sitting, have pt run heel of one foot over the shin of opposite leg

23. Deep Tendon Reflexes Assessment • Deep tendon reflexes- Have pt. in relaxed position, with joint supported. • DTR – compare L to R • Short blow with reflex hammer to the muscle’s insertion tendon (wrist action) • Reinforcement – Have pt. contract muscles not being tested this aids in relaxing muscles to be tested

24. Scale 0 - 4+ 0 = absent, 1+ = diminished 2+ = average 3+ = brisk 4+ = hyperactive, clonus. DTR Assessment

25. DTR Assessment Deep Tendon Reflexes (DTR) • Biceps – Forearm flexes at elbow. • Triceps – Forearm extends at elbow. • Brachioradialis –Slight flexion of forearm at elbow and forearm pronation. • Patella – leg extends at knee. • Achilles – Plantar flexion.

26. Clonus Testing • Perform clonus testing if previous reflex testing reveals Hyperactivity • Relax muscle of calf • Briskly dorsiflex foot and hold stretch • Clonus = rapid rhythmic contractions • NO CLONUS ( no movement) = normal

27. Superficial Cutaneous Reflex Assessment • Abdominal - Umbilicus shifts toward stimulus. • Cremasteric – Testicle on same side of stimulation rises. • Babisnki (Plantar) – Toes flex.

28. Summary • Neurological assessment includes: • Mental status • Cognitive assessment • Cranial nerves • Motor Functions & Muscle tone • Sensory Function • Cerebellar Function • DTR & superficial cutaneous reflexes